Concrete pile construction



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Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE CONCRETE PILECONSTRUCTION Application November 9, 1934, Serial No. 752,224

8 Claims.

Ihis invention pertains to the construction of concrete piles of unusuallength.

In practice there is a rather well-delined limit to the length ofpre-cast concrete piles which may be economically handled. One of thelimitations is, of course, the increased mass which is the naturalresult of increased length. Then there is a very serious problem in theuse of precast piles of extreme length for the reason that an excessiveamount of reinforcement is required to make the pile strong enough tostand the stresses due to handling, the amount of reinforcing steelrequired for that purpose being greater than the amount required in thepile after it is in use. Furthermore, the necessary equipment forhandling extra long heavy piles is extremely expensive, due not only tothe weights to be handled but to the extreme height of the driver andhandling derricks.

Attempts have been made to overcome the above difficulties by drivingsteel pipes to be lled with concrete after driving. But even though thattype `of pile offers no great handling diniculties it has its economicallimitations due to the cost of the pipe, which becomes prohibitivebeyond certain dimensions. The present invention seeks to solve theproblem by disclosing a particular kind of composite pile having a lowerpipe section, and a concrete upper section which is made as long as canbe handled, thus making the pipe section as short as possible in orderto reduce cost. Composite piles having pipe sections and pre-castconcrete sections are not broadly new, but according to previouspractice, the pre-cast concrete member would usually be driven rst andthe pipe section placed on top of the pre-cast member, since it iseasier to put the long member in the ground rst and then drive thecombined unit to a penetration suf- .:cient to carry the ultimate load.However, this involves stopping the driving when the pile has attained aposition that makes it necessary to add the top section. When suchdriving ceases, the ground normally grips the pile to a degree thatmakes it almost impossible to re-start it, particularly when the pilemass is so much in excess of the mass of the driving hammer.

By driving the hollow pipe first, as in the present invention, thisparticular objection is overcome, rst, because the mass of the hollowpipe is not so excessive with relation to the mass of the hammer, andsecond, on account of the nature of the steel pipe the vibrationsinduced by the hammer blows tend to loosen the shell from the groundwhich grips it. Furthermore,

the upper concrete section is in the form of a hollow shell, thusgreatly reducing its mass and permitting the driving of pile lengthsnever before possible, so far as I am aware.

Broadly then, the invention contemplates the 5 use of an upper pre-castconcrete section as long as can be handled, and a lower section of steelpipe. The upper pre-cast concrete section is made in the form of ahollow shell to reduce its weight and to provide a passage or conduit l0therethrough by means of which the lower pile section may be llled withconcrete after the driving is completed, the lling, of course, extendinginto the upper concrete shell so as to form a monolithic core andintegral with the l5 pipe comprising the lower shell, and with theconcrete comprising the upper shell, the core extending as far asdesired into the upper shell.

The lower end of the concrete shell is provided with a tubular tenonwhich extends a certain 270 distance into the top of the lower pipesection to keep upper and lower shells in alignment. Also, the upper endof the tenon is encased in a steel sleeve, and reinforcing rodsextending through the pre-cast concrete shell are welded 25 to thesleeve.Y The sleeve is in abutting relationship with the top of thelower pipe shell in order to transmit the driving effect to the pipe.Engagement of the sleeve with the upper concrete shell is accomplishedby the reinforcing rods 30 welded to the sleeve, by abutment of theupper end of the sleeve with a shoulder on the concrete shell, and bythe bond between the sleeve and the concrete of the tenon.

Further and other objects and advantages will 35 be apparent from thespecication and claims, and from the accompanying drawings whichillustrate what is now considered the preferred embodiment of theinvention.

Fig. 1 is an elevation of the completed pile, 40 the lower section beingcircular in cross-section and the upper section being square incross-section.

Fig. 2 is a cross-section of the pile taken on the shortest diameter ofthe upper square section and showing only the short set of reinforcingbars, designated B.

Fig, 3 is a cross-section taken on the long diameter of the squaresection and showing only the long reinforcing bars, designated A, whichare placed in the corners of the square section.

Fig. 4 is a cross-section on line 4 4 of Fig. 2, but showing bars A andB.

Fig. 5 is a cross-section on line 5 5 of Fig. 2, but showing bars A andB.

Fig. 6 is a cross-section on line 6 6 of Fig. 3, but showing bars A andB.

Fig. 7 is a cross-section on line 'i-'l of Fig. 2, but showing bars Aand B.

Fig. 8 is a cross-section of the upper end of the lower section andlower end of the upper section of the pile with modified form ofreinforcement.

Fig. 9 is a cross-section on line 9 9 of Fig. 8.

In the drawings, 2t designates the pipe comprising the lower shell, 22the driving point fitted to the lower end of shell 20, and 2d. a collarsurrounding and welded to the upper end of shell 20, the collarprojecting above the top of shell 2U.

26 designates the square pre-cast concrete upper shell. The lower end ofshell 26 beginning at the point 28 is shaped in the form of an annulartenon 3U of such diameter as to fit snugly within the upper end of steelshell 20, thereby holding the upper and lower shells in alignment duringthe driving operation. The upper part of tenon 30 is encased in a steelsleeve 32, this sleeve being of the same external diameter as shell 20so that when the tenon is slipped down into shell 2?, sleeve 32 willenter collar 24 and rest in abutting relationship with the top of shell2B at point 34 (Figs. 2 and 3). The upper end of sleeve 32 is inabutting relationship with a shoulder 28 on the upper concrete shell.

In the illustrated embodiment of the invention, the upper concrete shellis equipped with two sets of reinforcing rods. The rods comprising setA, Figs. 3, 4, 5, 6 and 7, extend from the bottom of the tenon upwardlyinto the body of the shell where they are bent so as to occupy positionsnear the corners of the square shell (Figs. 3 and 4). These rods, whenpassing through the upper part of the tenon are bent into contact withsleeve 32 and are welded to the sleeve as indicated at 36. The other setof reinforcing rods designated B extend from the bottom of the tenon upthrough the tenon and for a limited distance into the upper shell atpoints from rods A. Rods B are brought into contact with, and welded to,sleeve 32 at points designated 38, Fig. 2. The vertical reinforcing barsare encircled by reinforcing rings 40, 42 and 52 in the usual manner.

In practice, lower shell 2G is rst driven. When its upper end approachesground level, the upper concrete shell 25 is mounted on shell 2E), thetenon 3E (bevelled at its lower end as at 44 so as to easily enter shell2Q), passes down into shell 2li until the lower end of sleeve 32 rests,within collar 24, at 34 on the top of shell 2). Then with the tenonholding the upper and lower shells in alignment, the two shells aredriven into the ground by blows applied to the upper end of the concreteshell. The driving effect is transmitted from the upper concrete shellt0 the lower pipe shell by the abutting contact of sleeve 32 with thetop of shell 29. The concrete comprising upper shell 26 transmits thedriving effect to sleeve 32 by means of bars A and B which are embeddedin the concrete and welded to the sleeve, by abutment of the top ofsleeve 32 with shoulder 28, and by the bond between the concrete and theinside of the sleeve, which is very intimate because the concrete iscast into sleeve 32. Collar 24 on the outside of the joint betweensleeve 32 and shell 26, and tenon '39 on the inside of that same joint,serve to hold sleeve 32 and shell 25 in proper alignment during driving.

In the modification shown in Figs. 8 and 9, the reinforcing bars A and Bare not welded to the sleeve, the bonded relationship between theconcrete and the sleeve being amplified sufficiently for some conditionsby means of spaced radiating vertical plates 46 welded to the shell 32as at 43 and extending radially inwardly, as best shown in Fig. 9.

After the driving of the upper and lower shells is completed, the lowerpipe section and the cavity in the upper concrete section are filledwith plastic concrete 53 which, when hardened, forms a monolithic coreintegral with the upper and lower shells to form the completed pile.

It is to be understood that the invention is not limited to the specificembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as dened by the following claims.

1. A composite pile comprising a lower shell of tubular steel, an uppershell of pre-cast concrete extending above said steel shell, and amonolithic core of concrete within said shells.

2. A composite pile comprising a lower shell of tubular steel, an uppershell of pre-cast concrete, an annular tenon projecting downwardly fromthe lower end of said upper shell into the upper end of said lowershell, and a monolithic core of concrete within said shells and saidtenon.

3. The invention set forth in claim 2 in which said tenon is at leastpartially encased in a steel sleeve.

4. A composite pile comprising a lower shell of tubular steel, an uppershell of pre-cast concrete, an annular tenon projecting downwardly fromthe lower end of said upper shell into the upper end of said lowershell, a steel sleeve at least partially encasing said tenon, steelreinforcing bars welded to said sleeve and extending into the concreteof said upper shell, and a monolithic core of concrete within saidshells and said tenon.

5. A composite pile comprising a lower shell of tubular steel, an uppershell of pre-cast concrete, an annular tenon projecting downwardly fromthe lower end of said upper shell into the upper end of said lowershell, a steel sleeve at least partially encasing said tenon, the lowerend of said sleeve being in abutting relationship with the upper end ofsaid steel shell, and a monolithic core of concrete within said shellsand said tenon.

6. The invention set forth in claim 5 in which the upper end of saidsteel lower shell is provided with an annular collar welded thereto andextending upwardly around the lower end of said sleeve.

'7. The invention set forth in claim 5 in which said upper concreteshell is provided with an annular shoulder against which the upper endof said sleeve is in abutting relationship.

8. A composite pile comprising a lower shell of tubular steel, an uppershell of pre-cast con'- crete, an annular tenon projecting downwardlyfrom the lower end of said upper shell into the upper end of said lowershell, a steel sleeve around the upper part of said tenon, the lower endof said sleeve abutting the top of said lower shell and the upper end ofsaid sleeveV abutting said upper shell, reinforcing bars welded to saidsleeve and extending into said upper shell, and a monolithic core ofconcrete within said shells and said tenon.

HENRY A. CHRISTIE.

